Quick atmospheric correction (QUAC) code for VNIR-SWIR spectral imagery: Algorithm details

We describe an in-scene method for VNIR-SWIR atmospheric correction for multi- and hyperspectral imagery, dubbed QUAC (QUick Atmospheric Correction). It determines the atmospheric compensation parameters directly from the information contained within the scene using the observed pixel spectra. The approach is based on the empirical finding that the mean spectrum of a collection of diverse material spectra, such as the endmember spectra in a scene, is essentially invariant from scene to scene. It allows the retrieval of reasonably accurate reflectance spectra even when the sensor does not have a proper radiometric or wavelength calibration, or when the solar illumination intensity is unknown. The computational speed of the atmospheric correction method is significantly faster than for the first-principles methods, making it potentially suitable for real-time applications. QUAC is applied to atmospherically correction of example AVIRIS and HyMap data sets. Comparisons to the physics-based FLAASH code are shown.